20 simulators

The lab bench.

Push a parameter and watch the physics answer. Every simulator shows its formulas and the assumptions it makes, so you know where the model stops being true.

Energy systems
Gridfall
Run a national grid with real DC power flow. A coach shows you how.
Biology
Flocking
Boids: three local rules, and a murmuration emerges. Chase it with a hawk.
Physics
Falling Sand
Pour sand, water, oil, fire, lava and acid, and watch them react.
Biology
Epidemic
An outbreak in a town of dots, against the SIR model. Flatten the curve.
Cybersecurity
Blacksite
Incident response in a data hall. Real investigation, fictional hosts.
Mechanics
Projectile Motion
Launch angle, speed, gravity and air drag, with the trajectory traced live.
Physics
Pendulum Lab
Full nonlinear pendulum against the small-angle formula, with a phase plot.
Astronomy and space
Orbit Sandbox
Throw a satellite around a planet. Circular, elliptical or escape.
Electronics
RC Circuit
Charge and discharge a capacitor. Watch the time constant happen.
Mechanical engineering
Gear Train
Mesh up to four gears. Ratios, output speed and torque, animated.
Physics
Wave Interference
Add two waves. Beats, standing waves and cancellation on one screen.
Structural
Beam Load
Load a simply supported beam. Reactions, bending moment and deflection.
Physics
Double Pendulum
Chaos you can drag. A ghost twin shows how fast prediction breaks.
Astronomy and space
Gravity Sandbox
Throw planets around a star. Binary stars, the figure eight, collisions.
Physics
Ray Optics
Refraction, total internal reflection and a lens bench with real images.
Mathematics
Fourier Drawing
Draw any shape and watch spinning circles redraw it.
Mathematics
Game of Life
Conway's cellular automaton. Draw cells, load guns and spaceships, change the rules.
Physics
Gas in a Box
Hundreds of colliding atoms. Temperature, pressure and the speed curve.
Electronics
Electric Field
Drag charges and watch field lines and equipotentials redraw live.
Mechanical engineering
Resonance
Shake a spring at its natural frequency and watch the amplitude climb.